Drill presses are known having a base from which extends upwardly a vertical column along which the head of the drill press is movable and can be locked in a selected position. The head houses an electric motor and appropriate transmission for rotatably driving a toolholder chuck. The chuck is movable relative to the head along an axis parallel to the column for executing drilling operations. This axial movement of the chuck is effected by a pivoted control lever operating through a rack-and-pinion mechanism.
It is known to provide such drill presses with electronic controls and digital displays, and to include a safety device for the operator in the event of a drill bit becoming locked or stuck in the workpiece, either right at the commencement of drilling or at some point during performance of the drilling operation. The safety device protects the drive motor against overload.
In the event that one or more such safety devices are triggered, there is automatically brought about a drop in the output of the motor to a safety level. After such triggering, it is up to the operator to find a way of temporarily increasing output from the motor in order to obtain release of the drill bit.